In recent years, the researchers are interested in making light Olefins (C2-C4) from Syngas other than the methods of catalytic cracking of naphtha and dehydrogenation of alkanes. The catalysts of iron and cobalt mixed with Manganese used for conversion of Synthesis Gas to hydrocarbons have been extensively studied because of their characteristics such as selective formation of light Olefins in the C2-C4 range particularly Propene with a suppressed C1 product . Mn has been widely used as one of the promoters for unsupported Fe-based FT catalysts, particularly in promoting the production of C2-C4 Olefins. Some investigators have been working on operation parameters of Cobalt-based catalysts and showed that the Olefin contents of the product spectrum decreased with increasing pressure . In this work, Co-MnFe/γ-Al2O3 catalyst was prepared a wet impregnation method. The catalyst was characterized using varying techniques such as XRD,H2-TPR, SEM and BET techniques. The effects of temperature, support, Mn to Co ratio on the catalytic performance of these catalysts have been investigated. It has been shown that [Mn]/[Co] molar ratio are important in controlling the catalytic activity . The catalyst gave the highest catalytic performance for the conversion of synthesis gas to light olefins.